<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Cache
 * @subpackage Zend_Cache_Backend
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Xcache.php 23775 2011-03-01 17:25:24Z ralph $
 */

/**
 * @see Zend_Cache_Backend_Interface
 */
require_once 'Zend/Cache/Backend/Interface.php';

/**
 * @see Zend_Cache_Backend
 */
require_once 'Zend/Cache/Backend.php';

/**
 * @package    Zend_Cache
 * @subpackage Zend_Cache_Backend
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Cache_Backend_Xcache extends Zend_Cache_Backend implements Zend_Cache_Backend_Interface {
	
	/**
	 * Log message
	 */
	const TAGS_UNSUPPORTED_BY_CLEAN_OF_XCACHE_BACKEND = 'Zend_Cache_Backend_Xcache::clean() : tags are unsupported by the Xcache backend';
	const TAGS_UNSUPPORTED_BY_SAVE_OF_XCACHE_BACKEND = 'Zend_Cache_Backend_Xcache::save() : tags are unsupported by the Xcache backend';
	
	/**
	 * Available options
	 *
	 * =====> (string) user :
	 * xcache.admin.user (necessary for the clean() method)
	 *
	 * =====> (string) password :
	 * xcache.admin.pass (clear, not MD5) (necessary for the clean() method)
	 *
	 * @var array available options
	 */
	protected $_options = array ('user' => null, 'password' => null );
	
	/**
	 * Constructor
	 *
	 * @param  array $options associative array of options
	 * @throws Zend_Cache_Exception
	 * @return void
	 */
	public function __construct(array $options = array()) {
		if (! extension_loaded ( 'xcache' )) {
			Zend_Cache::throwException ( 'The xcache extension must be loaded for using this backend !' );
		}
		parent::__construct ( $options );
	}
	
	/**
	 * Test if a cache is available for the given id and (if yes) return it (false else)
	 *
	 * WARNING $doNotTestCacheValidity=true is unsupported by the Xcache backend
	 *
	 * @param  string  $id                     cache id
	 * @param  boolean $doNotTestCacheValidity if set to true, the cache validity won't be tested
	 * @return string cached datas (or false)
	 */
	public function load($id, $doNotTestCacheValidity = false) {
		if ($doNotTestCacheValidity) {
			$this->_log ( "Zend_Cache_Backend_Xcache::load() : \$doNotTestCacheValidity=true is unsupported by the Xcache backend" );
		}
		$tmp = xcache_get ( $id );
		if (is_array ( $tmp )) {
			return $tmp [0];
		}
		return false;
	}
	
	/**
	 * Test if a cache is available or not (for the given id)
	 *
	 * @param  string $id cache id
	 * @return mixed false (a cache is not available) or "last modified" timestamp (int) of the available cache record
	 */
	public function test($id) {
		if (xcache_isset ( $id )) {
			$tmp = xcache_get ( $id );
			if (is_array ( $tmp )) {
				return $tmp [1];
			}
		}
		return false;
	}
	
	/**
	 * Save some string datas into a cache record
	 *
	 * Note : $data is always "string" (serialization is done by the
	 * core not by the backend)
	 *
	 * @param string $data datas to cache
	 * @param string $id cache id
	 * @param array $tags array of strings, the cache record will be tagged by each string entry
	 * @param int $specificLifetime if != false, set a specific lifetime for this cache record (null => infinite lifetime)
	 * @return boolean true if no problem
	 */
	public function save($data, $id, $tags = array(), $specificLifetime = false) {
		$lifetime = $this->getLifetime ( $specificLifetime );
		$result = xcache_set ( $id, array ($data, time () ), $lifetime );
		if (count ( $tags ) > 0) {
			$this->_log ( self::TAGS_UNSUPPORTED_BY_SAVE_OF_XCACHE_BACKEND );
		}
		return $result;
	}
	
	/**
	 * Remove a cache record
	 *
	 * @param  string $id cache id
	 * @return boolean true if no problem
	 */
	public function remove($id) {
		return xcache_unset ( $id );
	}
	
	/**
	 * Clean some cache records
	 *
	 * Available modes are :
	 * 'all' (default)  => remove all cache entries ($tags is not used)
	 * 'old'            => unsupported
	 * 'matchingTag'    => unsupported
	 * 'notMatchingTag' => unsupported
	 * 'matchingAnyTag' => unsupported
	 *
	 * @param  string $mode clean mode
	 * @param  array  $tags array of tags
	 * @throws Zend_Cache_Exception
	 * @return boolean true if no problem
	 */
	public function clean($mode = Zend_Cache::CLEANING_MODE_ALL, $tags = array()) {
		switch ($mode) {
			case Zend_Cache::CLEANING_MODE_ALL :
				// Necessary because xcache_clear_cache() need basic authentification
				$backup = array ();
				if (isset ( $_SERVER ['PHP_AUTH_USER'] )) {
					$backup ['PHP_AUTH_USER'] = $_SERVER ['PHP_AUTH_USER'];
				}
				if (isset ( $_SERVER ['PHP_AUTH_PW'] )) {
					$backup ['PHP_AUTH_PW'] = $_SERVER ['PHP_AUTH_PW'];
				}
				if ($this->_options ['user']) {
					$_SERVER ['PHP_AUTH_USER'] = $this->_options ['user'];
				}
				if ($this->_options ['password']) {
					$_SERVER ['PHP_AUTH_PW'] = $this->_options ['password'];
				}
				
				$cnt = xcache_count ( XC_TYPE_VAR );
				for($i = 0; $i < $cnt; $i ++) {
					xcache_clear_cache ( XC_TYPE_VAR, $i );
				}
				
				if (isset ( $backup ['PHP_AUTH_USER'] )) {
					$_SERVER ['PHP_AUTH_USER'] = $backup ['PHP_AUTH_USER'];
					$_SERVER ['PHP_AUTH_PW'] = $backup ['PHP_AUTH_PW'];
				}
				return true;
				break;
			case Zend_Cache::CLEANING_MODE_OLD :
				$this->_log ( "Zend_Cache_Backend_Xcache::clean() : CLEANING_MODE_OLD is unsupported by the Xcache backend" );
				break;
			case Zend_Cache::CLEANING_MODE_MATCHING_TAG :
			case Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG :
			case Zend_Cache::CLEANING_MODE_MATCHING_ANY_TAG :
				$this->_log ( self::TAGS_UNSUPPORTED_BY_CLEAN_OF_XCACHE_BACKEND );
				break;
			default :
				Zend_Cache::throwException ( 'Invalid mode for clean() method' );
				break;
		}
	}
	
	/**
	 * Return true if the automatic cleaning is available for the backend
	 *
	 * @return boolean
	 */
	public function isAutomaticCleaningAvailable() {
		return false;
	}

}
